Florida Senator Marco Rubio made a bid to try and block Donald Trump from winning the Republican presidential nomination, telling his supporters in Ohio to give their votes to John Kasich next Tuesday.

“Clearly John Kasich has a better chance of stopping Donald Trump in Ohio than I do,” Rubio said during an event Friday in West Palm Beach, Florida.

He said he hadn’t consulted with Kasich, Ohio’s governor, about the gambit, nor has he spoken to Texas Sen. Ted Cruz about forming a so-called unity ticket aimed at stopping Trump.

Kasich spokesman Rob Nichols said the governor didn’t seek Rubio’s help and won’t need it to carry his home state. Kasich isn’t reciprocating by urging his backers in Florida to go with Rubio.

“We’re going to win Ohio without his help,” Nichols said.

Ohio and Rubio’s home state of Florida are among five states holding primaries on March 15 and a Trump sweep would give the real estate mogul an all-but-insurmountable lead in delegates needed to win the nomination.

Next Tuesday’s primaries have more than 350 delegates up for grabs. Florida and Ohio are winner-take-all contests, and Trump currently holds an advantage in both in recent polls. Rubio, who has won just two of the first 26 nominating contests, may be facing elimination if he fails to win his home state.

Trump has amassed 459 of the 1,237 delegates needed to claim the Republican nomination, followed by Cruz with 360, Rubio with 152 and Kasich with 54, according to a tally compiled by the Associated Press.

Some Republicans committed to stopping Trump, including 2012 presidential nominee Mitt Romney, have suggested supporters should vote for whichever candidate is strongest against Trump in a particular state. Such a strategy could lead to splitting enough delegates to call for a contested convention.

Trump is favored by 36.5 percent of Ohio Republicans, giving him a 2.5 percentage point lead over Kasich in Ohio, according to a RealClearPolitics average of recent polls in the state. Rubio is last, garnering 7 percent.

Kasich is spending Friday through Monday campaigning throughout Ohio, while Trump has rallies planned in Cincinnati, Dayton and Cleveland this weekend.